Please visit here for my logic analyzer comparison from a couple years ago but updated April 2012.
I own the Logic Port, Saleae logic and now the IKALOGIC Scanalogic-2 PRO.
The logic port, top image, is 500mhz fast with a tiny buffer, up to 2k transitions.
The Saleae, middle image, is 24mhz slow with more or less an unlimited buffer.
The IKALOGIC Scanalogic-2 PRO, bottom image, is a 20mhz with 256k per channel.